Tandem-compound-engine bushing.



No. 775.376 PATENTED NOV. 22, 1904. J. METZGER.

TANDEM COMPOUND ENGINE BUSHING.

APPLICATION FILED AUG. 8, 1904.

N0 MODEL.

W/TNESES I INVENTOH W69, (/2950 fi/6/zyer W1 y VG/n H m k UNITED STATESPatented November 22, 1904:.

JOHN METZGER, OF TACOMA, IVASHINGTON.

TANDEM-COMPOUND-ENGINE BUSHING.

SPECIFICATION forming part of Letters Patent No. 775,376, dated November22, 1904.

Application filed August 8, 1904.

T (ZZZ whmn it may concern.-

Be it known that 1, JOHN METZGER, a citizen of the United States ofAmerica, residing at Tacoma, in the county of Pierce and State of\Vashington, have invented certain new and useful Improvements inTandem-Compound-Engine Bushings, of which the following is aspecification,reference being had therein to the accompanying drawings.

This invention relates to the bushing placed around the piston-rodbetween the high and low pressure cylinders in a tandem compoundsteam-engine, and has for its objects to increase the efficiency of thebushing by decreasing the leak of steam from the high to the lowpressure cylinder and to increase the life of the bushing by making itself-adjusting and to decrease the wear of the pistonrod at the end nearthe high-pressure piston by decreasing the leak of steam as abovestated.

I attain these objects by the devices illustrated in the accompanyingdrawings, in which Figure 1 is a vertical longitudinal section of thehigh and low pressure cylinders of a tandem compound engine equippedwith my improved bushing. Fig. 2 is an enlarged vertical longitudinalsection of, the bushing, and Fig. 3 is an end view thereof looking fromthe low-pressure cylinder toward the high-pressure cylinder.

Similar numerals of reference refer to similar parts throughout theseveral views.

One of the principal obstacles to the successful working of tandemcompound steamengines, especially locomotives, is found in thediiiiculty in keeping the highpressure steam from leaking through thebushing to the low-pressure cylinder when the pistons are on the inwardstroke, as shown in Fig. 1, because the full boiler-pressure is appliedto one side of the bushing, while the other side is connected to thecondenser or to the atmosphere through the exhaust. This unequalpressure is greatest when at the beginning of the inward stroke. Theusual construction As soon as this Serial No. 219,944. No modelfi riallywear the piston-rod near the high-pres-- sure piston and would thusreduce the efliciency of the engine every inward stroke.

In the drawings I have indicated the highpressure cylinder at 1, thelow-pressure cylinder at 2, the high-pressure piston at 3, thelow-pressure piston at 4, the piston'rod at 5, the steam-inlet passageat 6, the valve-chest and intermediate chamber at 7, the high-pressureValve at 8, the low-pressure valve at 9, the exhaust-passage at 10, thewall between the high and low pressure cylinders at 11, the cone in thehigh-pressure cylinder at 12, the passage through the wall 11 and thecone 12 at 18, and the recess in the wall 11 from the passage 13 at 14.

In none of the above parts have I changed the usual method ofconstructing the engine.

Referring principally to Figs. 2 and 3, it will be seen that my bushingis constructed in two parts, each part divided into three pieces. Thepart 15 of my bushing is nearest the low-pressure cylinder 2, andconsists of a short cylindrical sleeve with a short flange 16 engagingin the recess 14: in the wall 11. This part 15 does not fit tightly inthe passage 13, but fits the piston-rod except at the three points whereit is cut, Fig. 3. The flange 16 fits tightly against the side of therecess 1& except where it is cut. The flange 16 is practically half asthick as the recess 1 L.

The part 17 of the bushing is nearest the high-pressure cylinder 1 andconsists of a short cylindrical sleeve practically of the samedimensions as the sleeve of the part and has a flange 18, which isadapted to fit exactly into the recess 14 between the wall 11 and thecone 12, but which is recessed to accurate lit over the flanges 16 ofthe part 15. The part 17 is also cut into three pieces, and when theparts 15 and 17 are assembled they are arranged as shown in Fig. 3, sothat the open spaces between the pieces of the part 15 do not come nearthe similar open spaces between the pieces of the part 17, and they areretained in their proper relative positions by the dowelpin 19. Circularspiral springs 20 hold the pieces of the parts 15 and 17 together. Iprefer to use two such springs placed in grooves on the outside of thesleeves of each of the parts and 17.

It is evident that as the piston-rod 5 or the bushings 15 and 17 wearthe bushing will close around the piston-rod and will always keep asteam-tight joint along the rod between the two cylinders 1 and 2, andthe flanges will always form a steam-tight joint around the bushings.Further, the flange 18 of the part 17 nearest the high-pressure cylinderincloses the flange 16 of the part 15. As the pressure of the steamaround the part 17 is greater than the pressure around the part 15, thewear of the part 17 will tend to be greater than that of'the part 15;but as the flange 18 surrounds the flange 16 it immediately increasesthe pressure on the part 15, and thus distributes the pressure all alongthe bushing. This arrangement tends to stop the wear of the piston-rod 5at the point Where at present it always shows the greatest wearnamely,near the I highpressure piston. The flanges 16 and 18 prevent thepassage of steam around the outside of the bushing.

In practice I find that tandem compound locomotives fitted with mybushing have run for many months with no measurable wear to thepiston-rod and but very little to the bushing, whereas the samelocomotives needed a renewal of bushings every four weeks and thepiston-rods needed returning every six months. The advantage, therefore,of my bushing is apparent.

Having now described my invention, what I claim, and desire to secure byLetters Patent, is

In a tandem-compound-engine bushing, the combination with the wallbetween the high and low pressure cylinders having a pistonrod passagetherein and with a recess in the end of said passage nearest thehigh-pressure cylinder, a casting within said high-pressure cylinder andconstructed so as to continue the piston-rod passage and so as to formone side of said recess, a split bushing within said passage in saidwall and having a circular flange engaging in said recess, a splitbushing within said passage in said casting and having a flange ofgreater diameter than the flange on the first bushing and further havinga recess in said flange adapted to fit over said flange on said firstbushing and means for retaining said bushings from turning relatively toeach other.

In testimony whereof I afliX my signature in presence of two witnesses.

JOHN METZGER.

WVitnesses:

M. H. CoNY, WV. E. WVINDsoR.

